Patents by Inventor Ping Mei

Ping Mei has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6288435
    Abstract: A method and apparatus for reducing vertical leakage current in a high fill factor sensor array is described. Reduction of vertical leakage current is achieved by eliminating Schottky junction interfaces that occur between metal back contacts and intrinsic amorphous silicon layers. One method of eliminating the Schottky junction uses an extra wide region of N doped amorphous silicon to serve as a buffer between the metal back contact and the intrinsic amorphous silicon layer. Another method of eliminating the Schottky junction completely replaces the metal back contact and the N doped amorphous silicon layer with a substitute material such as N doped poly-silicon.
    Type: Grant
    Filed: December 28, 1999
    Date of Patent: September 11, 2001
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Jeng Ping Lu, Francesco Lemmi, Robert A. Street, James B. Boyce
  • Patent number: 6288417
    Abstract: Polycrystalline group III-nitride semiconductor materials such as GaN and alloys of GaN and other group III-nitrides are deposited as layers on polycrystalline and non-crystalline substrates. The polycrystalline GaN layers can be formed by solid-phase crystallizing amorphous material or by directly depositing polycrystalline material on the substrates. The polycrystalline GaN material can be incorporated in light-emitting devices such as light-emitting diodes (LEDs). LED arrays can be formed on large-area substrates to provide large-area, full-color active-matrix displays.
    Type: Grant
    Filed: January 7, 1999
    Date of Patent: September 11, 2001
    Assignee: Xerox Corporation
    Inventors: Norbert H. Nickel, Christian G. Van de Walle, David P. Bour, Ping Mei
  • Patent number: 6252215
    Abstract: A pixel circuit construction for image sensing includes a photosensor, an amplifier, a selector switch and, and a reset switch. The amplifier may be a single polycrystalline silicon (channel) transistor for high gain. The selector switch may also be a single polycrystalline silicon (channel) transistor for high conductivity. The reset switch may a single amorphous crystalline silicon (channel) transistor for low leakage current. The photosensor and amplifier may be connected to a shared bias line or may be connected to separate bias and drive lines, respectively. The selector and reset switches may be connected to a shared data line or may be connected to separate data and reset lines, respectively. Laser crystallization and rehydrogenation techniques are well suited to obtaining devices described herein. Gate line and drive voltage line synchronization is provided.
    Type: Grant
    Filed: April 28, 1998
    Date of Patent: June 26, 2001
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Andrew J. Moore, Raj B. Apte, Steven E. Ready, Robert A. Street, James B. Boyce
  • Patent number: 6236831
    Abstract: A method and apparatus for recycling marking surfaces such as office paper is described. The system scans a marking surface, determines the location of printing on the marking surface and deposits erasing material directly over the printing. Because the distribution of erasing material is confined to the printed areas, the use of erasing material is minimized. The described system can be easily adapted for use in traditional copying systems to recycle paper.
    Type: Grant
    Filed: June 29, 1999
    Date of Patent: May 22, 2001
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Jaan Noolandi, James B. Boyce
  • Patent number: 6177399
    Abstract: This invention relates to a process for cleaning textiles, which comprises applying a composition comprising a low molecular weight linear siloxane represented by the formula: CH3((CH3)2SiO)nSi(CH3)2CH3 wherein n is an integer from 1 to 7, and a cationic surfactant to stained textiles and heating it in the presence of an inorganic base compound at a temperature below which the textiles are deteriorated.
    Type: Grant
    Filed: September 20, 1999
    Date of Patent: January 23, 2001
    Assignee: Dow Corning Taiwan, Inc.
    Inventors: Wang Ping Mei, Peter S. Wu, Samuel N. Chiang
  • Patent number: 6140668
    Abstract: Amorphous and polycrystalline silicon (hybrid) devices are formed close to one another employing laser crystallization and back side lithography processes. A mask (e.g., TiW) is used to protect the amorphous silicon device during laser crystallization. A patterned nitride layer is used to protect the amorphous silicon device during rehydrogenation of the polycrystalline silicon. An absorption film (e.g., amorphous silicon) is used to compensate for the different transparencies of amorphous and polycrystalline silicon during the back side lithography. Device spacing of between 2 and 50 micrometers may be obtained, while using materials and process steps otherwise compatible with existing hybrid device formation processes.
    Type: Grant
    Filed: April 28, 1998
    Date of Patent: October 31, 2000
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Rene A. Lujan
  • Patent number: 6107641
    Abstract: An improved thin film transistor structure is provided having no source/gate or drain/gate overlap. A laser doping technique is applied to fabricate such transistors. Eliminating source/gate and drain/gate overlap significantly reduces or eliminates parasitic capacitance and feed-through voltage between source and gate. Short-channel a-Si:H thin film transistors may be obtained having high field effect mobilities. Improved pixel performance and pixel-to-pixel uniformity is provided.
    Type: Grant
    Filed: September 10, 1997
    Date of Patent: August 22, 2000
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Rene A. Lujan, James B. Boyce, Christopher L. Chua, Michael G. Hack
  • Patent number: 6051827
    Abstract: A pixel circuit construction for image sensing includes a photosensor, an amplifier, a selector switch and, and a reset switch. The amplifier may be a single polycrystalline silicon (channel) transistor for high gain. The selector switch may also be a single polycrystalline silicon (channel) transistor for high conductivity. The reset switch may a single amorphous crystalline silicon (channel) transistor for low leakage current. The photosensor and amplifier may be connected to a shared bias line or may be connected to separate bias and drive lines, respectively. The selector and reset switches may be connected to a shared data line or may be connected to separate data and reset lines, respectively. Laser crystallization and rehydrogenation techniques are well suited to obtaining devices described herein. Threshold response is provided.
    Type: Grant
    Filed: April 28, 1998
    Date of Patent: April 18, 2000
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Andrew J. Moore, Raj B. Apte, Steven E. Ready, Robert A. Street, James B. Boyce
  • Patent number: 6031248
    Abstract: A pixel circuit construction for image sensing includes a photosensor, an amplifier, a selector switch and, and a reset switch. The amplifier may be a single polycrystalline silicon (channel) transistor for high gain. The selector switch may also be a single polycrystalline silicon (channel) transistor for high conductivity. The reset switch may a single amorphous crystalline silicon (channel) transistor for low leakage current. The photosensor and amplifier may be connected to a shared bias line or may be connected to separate bias and drive lines, respectively. The selector and reset switches may be connected to a shared data line or may be connected to separate data and reset lines, respectively. Laser crystallization and rehydrogenation techniques are well suited to obtaining devices described herein.
    Type: Grant
    Filed: April 28, 1998
    Date of Patent: February 29, 2000
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Andrew J. Moore, Raj B. Apte, Steven E. Ready, Robert A. Street, James B. Boyce
  • Patent number: 6020223
    Abstract: A method of producing an improved thin film transistor structure is provided having no source/gate or drain/gate overlap. A laser-assisted doping technique is applied to fabricate such transistors. A radiation filter is employed, which is transparent to light at the photolithography wavelength, but reflective or opaque at the laser wavelength. Eliminating source/gate and drain/gate overlap significantly reduces or eliminates parasitic capacitance and feed-through voltage between source and gate. Short-channel a-Si:H thin film transistors may be obtained having high field effect mobilities. Improved pixel performance and pixel-to-pixel uniformity is provided.
    Type: Grant
    Filed: October 29, 1997
    Date of Patent: February 1, 2000
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Rene A. Lujan, James B. Boyce, Christopher L. Chua, Michael G. Hack
  • Patent number: 6019796
    Abstract: A method of producing an improved thin film transistor structure is provided having no source/gate or drain/gate overlap. A laser-assisted doping technique is applied to fabricate such transistors. A radiation filter is employed, which is transparent to light at the photolithography wavelength, but reflective or opaque at the laser wavelength. Eliminating source/gate and drain/gate overlap significantly reduces or eliminates parasitic capacitance and feed-through voltage between source and gate. Short-channel a-Si:H thin film transistors may be obtained having high field effect mobilities. Improved pixel performance and pixel-to-pixel uniformity is provided.
    Type: Grant
    Filed: October 29, 1997
    Date of Patent: February 1, 2000
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Rene A. Lujan, James B. Boyce, Christopher L. Chua, Michael G. Hack
  • Patent number: 6011531
    Abstract: This invention relates to methods and applications of forming clusters of pixels in 2-D sensing and display arrays. Using TFT switches having more than one predetermined electrical characteristics. The array formed according to these teachings being used in sensing, displaying, adjusting resolution, color selection, image processing, object recognition and filtering.
    Type: Grant
    Filed: October 21, 1996
    Date of Patent: January 4, 2000
    Assignee: Xerox Corporation
    Inventors: Ping Mei, James B. Boyce, Robert A. Street, David K. Fork
  • Patent number: 6005238
    Abstract: A pixel circuit construction for image sensing includes a photosensor, an amplifier, a selector switch and, and a reset switch. The amplifier may be a single polycrystalline silicon (channel) transistor for high gain. The selector switch may also be a single polycrystalline silicon (channel) transistor for high conductivity. The reset switch may a single amorphous crystalline silicon (channel) transistor for low leakage current. The photosensor and amplifier may be connected to a shared bias line or may be connected to separate bias and drive lines, respectively. The selector and reset switches may be connected to a shared data line or may be connected to separate data and reset lines, respectively. Laser crystallization and rehydrogenation techniques are well suited to obtaining devices described herein. Linearization of output response is provided.
    Type: Grant
    Filed: April 28, 1998
    Date of Patent: December 21, 1999
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Andrew J. Moore, Raj B. Apte, Steven E. Ready, Robert A. Street, James B. Boyce
  • Patent number: 5893948
    Abstract: The invention provides a method for forming a plurality of single silicon crystals over a substrate. The method forms a plurality of nucleation sites over the substrate. An amorphous silicon layer is formed over the substrate covering the plurality of silicon nucleation sites. The amorphous silicon layer is melted by using a laser beam and then crystallized to form the plurality of single silicon crystals. Each of the plurality of single silicon crystals correspond to one of the plurality of nucleation sites.
    Type: Grant
    Filed: April 5, 1996
    Date of Patent: April 13, 1999
    Assignee: Xerox Corporation
    Inventors: Norbert H. Nickel, Gregory B. Anderson, Steven E. Ready, James B. Boyce, Ping Mei
  • Patent number: 5871826
    Abstract: This invention relates to a method of altering the electrical characteristics of a material through a laser ablation process. It can achieve high doping levels and shallow junctions at low temperatures, which are desirable in the fabrication of thin film transistors.
    Type: Grant
    Filed: May 30, 1996
    Date of Patent: February 16, 1999
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Rene A. Lujan, James B. Boyce
  • Patent number: 5821135
    Abstract: A transparent substrate as formed on its front side a layer of amorphous silicon. A laser beam is used to irradiate through the backside of the transparent substrate in order to form buried nucleation sites within the amorphous silicon. The buried nucleation sites which are used as nucleation seeds are then used during a front side crystallization process in order to form large single silicon crystals over the substrate surface.
    Type: Grant
    Filed: October 16, 1996
    Date of Patent: October 13, 1998
    Assignee: Xerox Corporation
    Inventors: Ping Mei, Gregory B. Anderson, James B. Boyce, David K. Fork, Richard I. Johnson
  • Patent number: 5767877
    Abstract: A toner jet printer and method of use for printing images by manipulating individual toner particles using two-dimensional print cell arrays built by micro electro mechanical systems (MEMS) technologies. Toner particles are positioned by aerodynamic forces controlled by microvalves within each print cell by either selective or nonselective filling. If selectively filled, each cell is then heated or subjected to an aerodynamic force to eject the toner particles onto a paper substrate. If non-selectively filled, only those print cells corresponding to an intended image are addressed electronically to eject a toner particle from an addressed cell by aerodynamic forces controlled by valve actuation or by heating the print cell. Single color or multiple color printing can be achieved using the same cell array.
    Type: Grant
    Filed: August 13, 1996
    Date of Patent: June 16, 1998
    Assignee: Xerox Corporation
    Inventors: Ping Mei, David Kalman Biegelsen, James Buckley Boyce
  • Patent number: 5733641
    Abstract: The invention provides a buffered substrate that includes a substrate, a buffer layer and a silicon layer. The buffer layer is disposed between the substrate and the silicon layer. The buffer layer has a melting point higher than a melting point of the substrate. A polycrystalline silicon layer is formed by crystallizing the silicon layer using a laser beam.
    Type: Grant
    Filed: May 31, 1996
    Date of Patent: March 31, 1998
    Assignee: Xerox Corporation
    Inventors: David K. Fork, James B. Boyce, Ping Mei, Steve Ready, Richard I. Johnson, Greg B. Anderson
  • Patent number: 5366926
    Abstract: A low temperature process for dehydrogenating amorphous silicon using lasers. Dehydrogenation occurs by irradiating one or more areas of a hydrogenated amorphous silicon layer with laser beam pulses at a relatively low energy density. After the multiple laser pulse irradiation at a relatively low energy density, the laser energy density is increased and multiple irradiation at a higher energy density is performed. If after the multiple irradiation at the higher energy density the amorphous silicon hydrogen content is still too high, dehydrogenation proceeds by multiple irradiations at a yet higher energy density. The irradiation at the various energy densities can result in the formation of polysilicon due to melting of the amorphous silicon layer. As irradiation may be selectively applied to the amorphous silicon, an integral amorphous silicon-polysilicon structure may be formed.
    Type: Grant
    Filed: June 7, 1993
    Date of Patent: November 22, 1994
    Assignee: Xerox Corporation
    Inventors: Ping Mei, James B. Boyce, Richard I. Johnson, Michael G. Hack, Rene A. Lujan